PIE: A Lightweight Control Scheme To Address the Bufferbloat Problem
draft-ietf-aqm-pie-02

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Document Type Active Internet-Draft (aqm WG)
Last updated 2015-10-14 (latest revision 2015-08-10)
Replaces draft-pan-aqm-pie
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Intended RFC status Informational
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Internet Draft                            R. Pan, P. Natarajan, F. Baker
Active Queue Management               G. White, B. VerSteeg, M.S. Prabhu
Working Group                                C. Piglione, V. Subramanian
Intended Status: Standards Track                                        

Expires: February 11, 2016                               August 10, 2015

           PIE: A Lightweight Control Scheme To Address the 
                          Bufferbloat Problem 

                      draft-ietf-aqm-pie-02

Abstract

   Bufferbloat is a phenomenon where excess buffers in the network cause
   high latency and jitter. As more and more interactive applications
   (e.g. voice over IP, real time video streaming and financial
   transactions) run in the Internet, high latency and jitter degrade
   application performance. There is a pressing need to design
   intelligent queue management schemes that can control latency and
   jitter; and hence provide desirable quality of service to users. 

   This document presents a lightweight active queue management design,
   called PIE (Proportional Integral controller Enhanced), that can
   effectively control the average queueing latency to a target value.
   Simulation results, theoretical analysis and Linux testbed results
   have shown that PIE can ensure low latency and achieve high link
   utilization under various congestion situations. The design does not
   require per-packet timestamp, so it incurs very small overhead and is
   simple enough to implement in both hardware and software. 

Status of this Memo

   This Internet-Draft is submitted to IETF in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF), its areas, and its working groups.  Note that
   other groups may also distribute working documents as
   Internet-Drafts.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."
 

Pan et al.             Expires February 11, 2016                [Page 1]
INTERNET DRAFT                    PIE                    August 10, 2015

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Copyright and License Notice

   Copyright (c) 2012 IETF Trust and the persons identified as the
   document authors. All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
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   (http://trustee.ietf.org/license-info) in effect on the date of
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   carefully, as they describe your rights and restrictions with respect
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   described in the Simplified BSD License.

Table of Contents

   1. Introduction  . . . . . . . . . . . . . . . . . . . . . . . . .  4
   2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . .  5
   3. Design Goals  . . . . . . . . . . . . . . . . . . . . . . . . .  5
   4. The Basic PIE Scheme  . . . . . . . . . . . . . . . . . . . . .  6
     4.1 Random Dropping (ECN Support is described later in this 
         document)  . . . . . . . . . . . . . . . . . . . . . . . . .  6
     4.2 Drop Probability Calculation . . . . . . . . . . . . . . . .  7
     4.3 Latency Calculation  . . . . . . . . . . . . . . . . . . . .  8
     4.4 Protecting Bursts  . . . . . . . . . . . . . . . . . . . . .  9
     4.5 Exponential Decay Drop Probability . . . . . . . . . . . . .  9
   5. Optional Design Elements of PIE . . . . . . . . . . . . . . . .  9
     5.1 ECN Support  . . . . . . . . . . . . . . . . . . . . . . . . 10
     5.2 Departure Rate Estimation  . . . . . . . . . . . . . . . . . 10
     5.3 Turning PIE on and off . . . . . . . . . . . . . . . . . . . 12
     5.4 De-randomization . . . . . . . . . . . . . . . . . . . . . . 12
   6. Implementation Cost . . . . . . . . . . . . . . . . . . . . . . 13
   7. Future Research . . . . . . . . . . . . . . . . . . . . . . . . 14
   8. Incremental Deployment  . . . . . . . . . . . . . . . . . . . . 14
   9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 14
   10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 14
     10.1  Normative References . . . . . . . . . . . . . . . . . . . 15
     10.2  Informative References . . . . . . . . . . . . . . . . . . 15
 

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